| #### Chapter 15 |

| #### #### How then do the four genera complete Substance without qualifying it or even particularizing it? #### It has been observed that Being is primary, and it is clear that none of the four- Motion, Stability, Difference, Identity- is distinct from it. That this Motion does not produce Quality is doubtless also clear, but a word or two will make it clearer still. #### If Motion is the Act of Substance, and Being and the Primaries in general are its Act, then Motion is not an accidental attribute: as the Act of what is necessarily actual [what necessarily involves Act], it is no longer to be considered as the complement of Substance but as Substance itself. For this reason, then, it has not been assigned to a posterior class, or referred to Quality, but has been made contemporary with Being. #### The truth is not that Being first is and then takes Motion, first is and then acquires Stability: neither Stability nor Motion is a mere modification of Being. Similarly, Identity and Difference are not later additions: Being did not grow into plurality; its very unity was a plurality; but plurality implies Difference, and unity-in-plurality involves Identity. #### Substance [Real Being] requires no more than these five constituents; but when we have to turn to the lower sphere, we find other principles giving rise no longer to Substance (as such) but to quantitative Substance and qualitative: these other principles may be regarded as genera but not primary genera. ####  |